Can anyone recommend the best tool or tools for testing mobile apps and sites? I need to test them on Android and iOS devices, both web apps and mobile sites. I have seen numerous emulators and looked at the SDKs, but the emulators do not seem that accurate and I would prefer to find one tool to do everything if possible rather than installing multiple SDKs. Are any of the cloud based testing environments worth the money?

Thanks in advance for any advice you can provide.